Optimized synthesis of isocyanate microcapsules for self-healing application in epoxy composites

2020 ◽  
Vol 32 (6) ◽  
pp. 669-680 ◽  
Author(s):  
Yong Sun ◽  
Shugang Wang ◽  
Xiaosu Dong ◽  
Yuntao Liang ◽  
Wei Lu ◽  
...  
Keyword(s):  
Mechanical Test ◽  
Optical Microscope ◽  
Epoxy Composites ◽  
Self Healing ◽  
Accelerated Corrosion ◽  
Water Emulsion ◽  
Core Content ◽  
Accelerated Corrosion Test ◽  
Oil In Water Emulsion ◽  
Processing Properties

Microcapsules containing isophorone diisocyanate were fabricated in oil-in-water emulsion. The emulsification effect of different emulsifiers during the capsule synthesis was systematically investigated by optical microscope. Three kinds of shell materials were discussed to obtain the high core content, smooth-surfaced, and robust capsule by scanning electronic microscope and Fourier transform infrared spectroscopy. Self-healing performance of corresponding self-healing epoxy composites was fully evaluated by accelerated corrosion test and mechanical test. The results demonstrated that high core content and smooth-surfaced capsules with dense composite shell could be synthesized in polyvinyl alcohol emulsion, and the core content of the optimized capsules was determined as 71.3–84.6 wt% at the capsule size from 35 µm to 154 µm. In addition, the optimized capsules had good processing properties and the corresponding self-healing epoxy composites exhibited excellent core release and self-healing performance.

Melamine Resin-Walled Microcapsules Containing Styrene: Preparation and Characterization

2008 ◽  
Vol 47-50 ◽  
pp. 286-289 ◽  
Author(s):  
Hai Ping Wang ◽  
Yan Chao Yuan ◽  
Min Zhi Rong ◽  
Ming Qiu Zhang
Keyword(s):  
In Situ Polymerization ◽  
Weight Ratio ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Resonance Spectroscopy ◽  
Self Healing ◽  
Melamine Formaldehyde ◽  
Scanning Calorimetry ◽  
Water Emulsion ◽  
Core Content

For purposes of developing a novel self-healing chemistry for polymer composites, melamine-formaldehyde (MF) resin-walled microcapsules containing styrene were prepared by in-situ polymerization in an oil-in-water emulsion. Chemical structure of the microcapsules was identified by Fourier-transform infrared spectroscopy (FTIR) and proton magnetic resonance spectroscopy (1H NMR), respectively. In addition, scanning electron microscope (SEM) and optical microscope (OM) were used to investigate morphology and geometry of the product. The effects of dispersion rate, weight ratio of core to shell and emulsifier concentration were carefully analyzed. It was found that poly(melamine-formaldehyde) (PMF) microcapsules containing styrene were successfully synthesized through the proposed technical route, and their mean diameters fall in the range of 20~71 µm. The rough surface of the microcapsules is composed of agglomerated PMF nanoparticles. Both core content and size of the microcapsule can be adjusted by selecting different processing parameters. The highest loading of styrene in the capsules is about 60% and the emulsifier with lower molecular weight used to result in higher core content. In terms of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), thermal behavior and storage stability of the capsules were studied. The results indicated that the microcapsules can be handled up to 72 oC.

scholarly journals In situ poly(melamine-formaldehyde) microencapsulation of diglycidyl ether of bisphenol-A epoxy and pentaerythritol tetrakis(3-mercaptopropionate) for self-healing applications

2022 ◽  
Vol 1217 (1) ◽  
pp. 012017
Author(s):  
H Ghazali ◽  
K Ghazali ◽  
R Yusoff
Keyword(s):  
Bisphenol A ◽  
Soxhlet Extraction ◽  
Diglycidyl Ether ◽  
Self Healing ◽  
Melamine Formaldehyde ◽  
Scanning Calorimetry ◽  
Water Emulsion ◽  
Core Content ◽  
Oil In Water ◽  
Oil In Water Emulsion

Abstract In this study, microcapsules as potential candidates for self-healing agents were prepared by in situ polymerisation, taking place in oil-in-water emulsion. Poly(melamine-formaldehyde) is employed as shell material and diglycidyl ether of bisphenol A as polymerisable core materials and Pentaerythritol Tetrakis(3-Mercaptopropionate) as its hardener. The geometry, shell features, size distributions, core content, and the reactivity of the microcapsules were studied by scanning electron microscopy (SEM), optical microscopy (OM), Soxhlet extraction method and differential scanning calorimetry (DSC). Microcapsules with different sizes and distributions were obtained by adjusting the stirring speeds during the preparation stage. From the results, it was established that the spherical microcapsules fabricated using this technique, resulted in satisfactory size and shell structure with shell thickness of less than 2 μm. The microcapsules possess high core content at about 90 wt.% for each size range of microcapsules and it was also observed that the viscosity of the core content decreased at an elevated temperature. The results obtained in this work indicate that these microcapsules possess the characteristics that can be potentially used for self-healing applications.

Wear Resistance of Polymers With Encapsulated Epoxy-Amine Self-Healing Chemistry

2015 ◽  
Vol 82 (5) ◽  
Author(s):  
Nay Win Khun ◽  
He Zhang ◽  
Jinglei Yang
Keyword(s):  
Epoxy Resin ◽  
Epoxy Matrix ◽  
In Situ Polymerization ◽  
Wear Test ◽  
Epoxy Composites ◽  
Self Healing ◽  
Matrix Composites ◽  
Water Emulsion ◽  
Healing Agent ◽  
Oil In Water Emulsion

In this study, epoxy resin was microencapsulated through in situ polymerization in an oil-in-water emulsion, and amine was loaded into etched glass bubbles (GBs) as a curing agent for the microencapsulated epoxy resin. The purpose was to develop a two-component-self-healing system. The two healing agent carriers were co-incorporated in the epoxy matrix to form novel epoxy composites for tribological applications. The tribological results clearly showed that an increase in healing agent carrier content significantly decreased the friction and wear of the epoxy composites tested against a 6 mm steel ball under different normal loads. This was due to the self-lubricating and self-healing of the composites with released core liquids via the rupture of healing agent carriers during the wear test. It could be concluded that the co-incorporation of two healing agent carriers was a potential way to achieve a significant improvement in the tribological properties of epoxy matrix composites.

Microencapsulation of Epoxy Resins for Self-Healing Material

2010 ◽  
Vol 148-149 ◽  
pp. 1031-1035
Author(s):  
Yang Zhao ◽  
Wei Zhang ◽  
Le Ping Liao ◽  
Wu Jun Li ◽  
Yi Xin
Keyword(s):  
Epoxy Resins ◽  
In Situ Polymerization ◽  
Heating Temperature ◽  
Hot Water ◽  
Core Material ◽  
Agitation Rate ◽  
Self Healing ◽  
Water Emulsion ◽  
Oil In Water Emulsion

With the development of the embedded microcapsule concept for self-healing material, the preparation of microcapsule has been paid more attentions. A new series of microcapsules were prepared by in situ polymerization technology in an oil-in-water emulsion with polyoxymethylene urea (PMU) as shell material and a mixture of epoxy resins as core material. The PMU microcapsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electronic microscopy (SEM), particle size analyzer and thermo gravimetric analyzer (TGA) to investigate their chemical structure, surface morphology, size distribution and thermal stability, respectively. The results indicate that PMU microcapsules containing epoxy resins can be synthesized successfully. The optimized reaction parameters were obtained as follow: agitation rate 600 rpm, 60°C water bath, pH=3.5, core material 20ml and hot water dilution by in-situ polymerization. The size is around 116 μm. The rough outer surface of microcapsule is composed of agglomerated PMU nanoparticles. The microcapsules basically exhibit good storage stability at room temperature, and they are chemically stable before the heating temperature is up to approximately 200°C.

Preparation of Microcapsules for Self-Healing Polymers

2012 ◽  
Vol 729 ◽  
pp. 205-209
Author(s):  
Anna Czeller ◽  
Tibor Czigány
Keyword(s):  
Optical Microscopy ◽  
Ph Value ◽  
Low Ph ◽  
Wall Material ◽  
Self Healing ◽  
Reaction Conditions ◽  
Water Emulsion ◽  
Oil In Water ◽  
Oil In Water Emulsion ◽  
Polymerization Method

In this paper, melamin-formaldehyde microcapsules filled with pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) or epoxy were prepared via oil-in-water emulsion polymerization method. Two different routes were chosen from literature, and applied with some changes. The effects of modification of reaction conditions on the resulting capsules were studied. It was found that too low pH value in the emulsion causes burst polymerization of the wall material, without microcapsule formation. When pH was set to 4.5 spherical microcapsules were formed. Optical microscopy was used to evaluate the microcapsules.

The Impact of Different Polydimethylsiloxane Core Materials on the Properties of Melamine Formaldehyde Microcapsules

2016 ◽  
Vol 694 ◽  
pp. 58-63 ◽  
Author(s):  
Hafeez Ullah ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhammad Irfan Khan
Keyword(s):  
Core Material ◽  
Self Healing ◽  
Melamine Formaldehyde ◽  
Water Emulsion ◽  
Electron Dispersive Spectroscopy ◽  
Oil In Water ◽  
Ft Ir ◽  
Oil In Water Emulsion ◽  
The Impact ◽  
Thermal Stability Of

Three different functionalized polydimethylsiloxane based probable self-healing materials were encapsulated by oil-in-water emulsion polymerization melamine-formaldehyde (MF) microcapsules for future applications in self-healing composites systems. The diameter and morphology, thermal properties, and structural analysis of the synthesized microcapsules were determined by scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and electron dispersive spectroscopy (EDS). The results showed that nature of core material plays an important role in the morphology and thermal stability of the microcapsules.

scholarly journals Robust synthesis of epoxy resin-filled microcapsules for application to self-healing materials

2016 ◽  
Vol 374 (2061) ◽  
pp. 20150083 ◽  
Author(s):  
Patryk A. Bolimowski ◽  
Ian P. Bond ◽  
Duncan F. Wass
Keyword(s):  
Epoxy Resin ◽  
Size Distribution ◽  
Fibre Composite ◽  
Diglycidyl Ether ◽  
High Yield ◽  
Self Healing ◽  
Carbon Fibre Composite ◽  
Scanning Calorimetry ◽  
Water Emulsion ◽  
Oil In Water Emulsion

Mechanically and thermally robust microcapsules containing diglycidyl ether bisphenol A-based epoxy resin and a high-boiling-point organic solvent were synthesized in high yield using in situ polymerization of urea and formaldehyde in an oil-in-water emulsion. Microcapsules were characterized in terms of their size and size distribution, shell surface morphology and thermal resistance to the curing cycles of commercially used epoxy polymers. The size distribution of the capsules and characteristics such as shell thickness can be controlled by the specific parameters of microencapsulation, including concentrations of reagents, stirrer speed and sonication. Selected microcapsules, and separated core and shell materials, were analysed using thermogravimetric analysis and differential scanning calorimetry. It is demonstrated that capsules lose minimal 2.5 wt% at temperatures no higher than 120°C. These microcapsules can be applied to self-healing carbon fibre composite structural materials, with preliminary results showing promising performance.

The Preparation and Research of Microcapsules in Self-Healing Coatings

2013 ◽  
Vol 800 ◽  
pp. 471-475
Author(s):  
Wang Rui ◽  
Qian Jin Mao ◽  
Qi Dong Liu ◽  
Xiao Yu Ma ◽  
Su Ping Cui ◽  
...  
Keyword(s):  
In Situ Polymerization ◽  
Core Material ◽  
Agitation Rate ◽  
Self Healing ◽  
Water Emulsion ◽  
Oil In Water ◽  
Infrared Spectrometer ◽  
Oil In Water Emulsion ◽  
The Impact

The self-healing polymer material which was embedded microcapsules possesses the ability to heal cracks automatically. The microcapsules were synthesized by in-situ polymerization in an oil-in-water emulsion with urea and formaldehyde as the raw shell material,and epoxy resin (E-51)/ xylene as the core material. The impact of stirring speed on the morphology and particle size of synthetic microcapsules were discussed by optical microscopy (OM), scanning electron microscopy (SEM), and Fourier-transform infrared spectrometer (FTIR).Microcapsules of 400~1500 um in diameter were produced by appropriate selection of agitation rate in the range of 300~600 r/min.

Fabrication of Polymeric Capsules Enclosing Eletrophoretic Particle Dispersion

2006 ◽  
Vol 949 ◽  
Author(s):  
Ru Qiao ◽  
Xiao Li Zhang ◽  
Ri Qiu ◽  
Yan Li ◽  
Young Soo Kang
Keyword(s):  
In Situ Polymerization ◽  
Urea Formaldehyde ◽  
Optical Microscope ◽  
Control Agent ◽  
Particle Dispersion ◽  
Polymerization Reaction ◽  
Water Emulsion ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Oil In Water Emulsion

ABSTRACTPoly(urea-formaldehyde) capsules enclosing electrophoretic particle dispersion were formed by carrying out an in-situ polymerization reaction in an oil-in-water emulsion. The internal dispersion was composed of pigment particles Yellow-14 modified by charge control agent to have superior electrophoresis velocity and the mixture of tetrachloroethylene and sec-butylbenzene, using Span 80 as the stabilizer and emulsifier. FE-SEM, TEM, and optical microscope (OM) were performed to investigate on the capsule size and surface morphology. Contact angle measurements showed that UF prepolymer deposited at the o/w interface to form hollow capsules only when the interfacial tension is large enough.

scholarly journals A Novel Self-Healing Epoxy System with Microencapsulated Epoxy and Imidazole Curing Agent

2007 ◽  
Vol 16 (5) ◽  
pp. 096369350701600 ◽  
Author(s):  
Min Zhi Rong ◽  
Ming Qiu Zhang ◽  
Wei Zhang
Keyword(s):  
Urea Formaldehyde ◽  
Weight Ratio ◽  
The Self ◽  
Wall Material ◽  
Self Healing ◽  
Epoxy System ◽  
Water Emulsion ◽  
Fracture Toughness Measurement ◽  
Healing Agent ◽  
Oil In Water Emulsion

This work reported a novel epoxy system that can perform a self-repairing operation against cracks at elevated temperature. For this purpose, a two-component healing agent consisting of microencapsulated epoxy and imidazole was pre-embedded into epoxy matrix. The microencapsulated epoxy was self-synthesized in advance using poly(urea-formaldehyde) as the wall material through a two-step polymerization approach in an oil-in-water emulsion. The performance of the self-healing epoxy composite was evaluated by fracture toughness measurement. It was found that the self-healing epoxy containing 20wt.% healing agent received a healing efficiency of 106% at the optimum capsulated imidazole-to-epoxy weight ratio of 0.2.

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